If $a + b = 5$ and $x + y = 3$, what is $-2x - 5a - 5b - 2y$ ?
Explanation: $= -5a - 5b - 2x - 2y$ $= (-5) \cdot (a + b) + (-2) \cdot (x + y)$ $= (-5) \cdot (5) + (-2) \cdot (3)$ $= -25 - 6$ $= -31$